Radioiodinated metaiodobenzylguanidine (MIBG) scintigraphy is known for its high specificity in detecting pheochromocytoma and other tumors of neural crest origin. We describe herein the first case of a definite adrenocortical adenoma that demonstrated false-positive uptake on MIBG scintigraphy. In addition, we reviewed all 13 reported cases showing false-positive uptake, and suggest that careful evaluation is needed before diagnosing a 'silent' or 'asymptomatic' pheochromocytoma.